INFO: rcu detected stall in inet_dgram_connect

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: ab758e10 Merge 4.9.184 into android-4.9
git tree: android-4.9
console output: https://syzkaller.appspot.com/x/log.txt?x=1566973ba00000
kernel config: https://syzkaller.appspot.com/x/.config?x=c2aad653d98c6f23
dashboard link: https://syzkaller.appspot.com/bug?extid=5063e5a90f7741a7fd60
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+5063e5...@syzkaller.appspotmail.com

INFO: rcu_preempt self-detected stall on CPU
0-...: (1 GPs behind) idle=5b9/140000000000001/0 softirq=61084/61086 fqs=34
(t=10500 jiffies g=23308 c=23307 q=507)
rcu_preempt kthread starved for 10425 jiffies! g23308 c23307 f0x0
RCU_GP_WAIT_FQS(3) ->state=0x1
rcu_preempt S28856 7 2 0x80000000
0000000000000083 ffff8801da6817c0 0000000000000000 ffff8801db721000
ffff8801da6b2f80 ffff8801db721018 ffff8801da697a70 ffffffff8280a5ce
ffff8801d9bebc28 ffff8801da6979b8 00ffffff81247fa1 ffff8801db7218f0
Call Trace:
[<000000009b5a9718>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
[<000000005eafcd7a>] schedule_timeout+0x513/0xe50 kernel/time/timer.c:1794
[<00000000bc3d9a9d>] rcu_gp_kthread+0xba5/0x20e0 kernel/rcu/tree.c:2235
[<00000000449e0f21>] kthread+0x278/0x310 kernel/kthread.c:211
[<00000000da893136>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375
Task dump for CPU 0:
syz-executor.3 R running task 28448 25840 2082 0x80000008
ffff8801db607c40 ffffffff81400c01 ffffffff81400a00 0000000000000001
0000000000000000 ffff8801db621000 dffffc0000000000 ffffffff830d6b88
ffffffff830d6bc0 ffff8801db607c60 ffffffff814010cc ffffffff830d6b40
Call Trace:
<IRQ> [ 829.574654] [<000000008a61e6ec>]
sched_show_task.cold+0x27f/0x327 kernel/sched/core.c:5312
[<000000003894b0cf>] dump_cpu_task+0x7a/0x7f kernel/sched/core.c:9076
[<00000000caee8502>] rcu_dump_cpu_stacks+0x193/0x1c3 kernel/rcu/tree.c:1303
[<0000000054b7ed2e>] print_cpu_stall kernel/rcu/tree.c:1446 [inline]
[<0000000054b7ed2e>] check_cpu_stall kernel/rcu/tree.c:1514 [inline]
[<0000000054b7ed2e>] __rcu_pending kernel/rcu/tree.c:3495 [inline]
[<0000000054b7ed2e>] rcu_pending kernel/rcu/tree.c:3559 [inline]
[<0000000054b7ed2e>] rcu_check_callbacks.cold+0x44a/0xd2f
kernel/rcu/tree.c:2888
[<00000000dd062903>] update_process_times+0x31/0x70
kernel/time/timer.c:1629
[<000000005a82a034>] tick_sched_handle.isra.0+0x4a/0xf0
kernel/time/tick-sched.c:151
[<00000000e5ee49f4>] tick_sched_timer+0x7a/0x130
kernel/time/tick-sched.c:1190
[<000000008ded2f57>] __run_hrtimer kernel/time/hrtimer.c:1255 [inline]
[<000000008ded2f57>] __hrtimer_run_queues+0x313/0xe00
kernel/time/hrtimer.c:1319
[<0000000006fb865e>] hrtimer_interrupt+0x1b6/0x450
kernel/time/hrtimer.c:1353
[<00000000ce3d490b>] local_apic_timer_interrupt+0x76/0xa0
arch/x86/kernel/apic/apic.c:937
[<0000000041297e94>] smp_apic_timer_interrupt+0x79/0xb0
arch/x86/kernel/apic/apic.c:961
[<00000000588a9bda>] apic_timer_interrupt+0x9d/0xb0
arch/x86/entry/entry_64.S:650
<EOI> [ 829.697094] [<000000008feace26>] ? rep_nop
arch/x86/include/asm/processor.h:589 [inline]
<EOI> [ 829.697094] [<000000008feace26>] ? cpu_relax
arch/x86/include/asm/processor.h:594 [inline]
<EOI> [ 829.697094] [<000000008feace26>] ? __read_seqcount_begin
include/linux/seqlock.h:114 [inline]
<EOI> [ 829.697094] [<000000008feace26>] ? raw_read_seqcount_begin
include/linux/seqlock.h:147 [inline]
<EOI> [ 829.697094] [<000000008feace26>] ? read_seqcount_begin
include/linux/seqlock.h:164 [inline]
<EOI> [ 829.697094] [<000000008feace26>] ? xfrm_state_find+0x12e4/0x2910
net/xfrm/xfrm_state.c:804
[<000000007c6b63aa>] xfrm_tmpl_resolve_one+0x1c7/0x7a0
net/xfrm/xfrm_policy.c:1500
[<00000000be75d7d4>] xfrm_tmpl_resolve net/xfrm/xfrm_policy.c:1544 [inline]
[<00000000be75d7d4>] xfrm_resolve_and_create_bundle+0x210/0x1e80
net/xfrm/xfrm_policy.c:1896
[<000000005a75e26b>] xfrm_bundle_lookup+0x3ae/0x1120
net/xfrm/xfrm_policy.c:2143
[<00000000e98b0e6e>] flow_cache_lookup+0x8a5/0x1000 net/core/flow.c:273
[<000000008ad2a50d>] xfrm_lookup+0x4a2/0xaf0 net/xfrm/xfrm_policy.c:2290
[<0000000010af1ee8>] xfrm_lookup_route+0x38/0x140
net/xfrm/xfrm_policy.c:2382
[<0000000085332c80>] ip_route_output_flow+0x93/0xa0 net/ipv4/route.c:2483
[<0000000051ed7cd7>] ip_route_connect include/net/route.h:297 [inline]
[<0000000051ed7cd7>] __ip4_datagram_connect+0x71f/0x1050
net/ipv4/datagram.c:51
[<000000000072159e>] ip4_datagram_connect+0x30/0x50 net/ipv4/datagram.c:92
[<00000000ae96b585>] inet_dgram_connect+0x119/0x1f0 net/ipv4/af_inet.c:545
[<00000000fb9f3474>] SYSC_connect net/socket.c:1576 [inline]
[<00000000fb9f3474>] SyS_connect+0x1a5/0x2e0 net/socket.c:1557
[<000000009cd3eb7d>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
[<0000000044ec4756>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.